RE: Questions of an ur-Q Kind

["Buchholz, Steven" <Steven.Buchholz@kla-tencor.com>]

... I don't know your service guy, so I'm assuming that he knows ZIP about
QTCs ... since I don't know him I may be totally wrong of course.  Yes, the
WX engine is interference, but it would probably take a broken belt to cause
any destructive interference.  Did he even check the timing between the cam
and the flywheel?  The F/TCU on the ur-q doesn't allow a lot of variation of
the distributor sender's timing window, so if it got too far out there's no
way you'd even get spark.  

Based on your description I would suspect that the more likely culprit is a
vacuum leak in the intake tract.  You probably had a little one before, but
when the engine backfired it probably made it even bigger.  The hose that
goes from the dome on top of the airflow sensor to the turbo inlet is the
prime suspect IME (BTDTxn) ... unfortunately this hose is probably a $150+
item, even at the Carlsen discount. See if you can get the engine to run
long enough to feel for suction and try to cover any holes with your hand to
see if the idle calms down (many times the leaks are difficult to see as
they look just like reinforcing ribs).  After losing a second one of these
on my car I figured that the primary source of the problem was the fact that
this hose runs fairly close to the turbo, and the heat of the turbo cooks
the hose and makes it brittle.  When I replaced the hose for the second time
I fashioned a heat shield from some heavy foil & fiberglass material ... and
haven't had a problem since.  My recommendation to you if this is indeed
your problem is to try to find the same sort of hose that Audi used (Graydon
Stuckey's intercooler => TB hose for MC engines looks similar in structure
but is too large in diameter) and rebuild your old hose.  Fortunately this
hose on the QTC is before the turbo, so it really doesn't have to hold above
atmospheric pressure ... it just needs to be reinforced so that it does not
collapse under vacuum.  

There may be some other problem that is causing your car to run poorly, like
a problem with the ground wire that attaches to the firewall end of the
intake manifold.  As an ur-q owner it is highly recommended that you get
copies of the QTC IST (Introductory Service Training) documents ... they are
available from Dyment Distributions (Dyment can be contacted at
800.544.8021).  Here is the order information:

Order #
WSP 451 556 00 - Audi Quattro Introductory Service Training Manual
[ur-quattro]
WSP 452 557 00 - Audi Quattro Maintenance and Adjustments Manual
[ur-quattro]

FYI, the former document gives a good overview of the systems of the car
(engine, brakes, drive train, etc.) ... with a good bit of theory of
operation, while the latter document describes things like torque specs and
troubleshooting procedures (like what to do when your fuel pump shuts down
at 4000 RPM :).  These documents go into such detail as to describe the
timing and boost maps that are programmed into the F/TCU.  I paid US$10 each
... a tremendous bargain IMO.  

If you want to check for bent valves it is possible that you would be able
to see the impact points on the piston crowns (I could make them out on the
piston crowns of the MC with the head off, but I really had to look in a
couple cases) ... a compression check would be the better method I would
think.  Here again, I would expect a qualified service person to know this
and do it without my having to ask if bent valves were the prime suspect.
I'll put my money on a fairly simple to repair problem though ... good luck
to you Douglas!

Steve Buchholz
San Jose, CA (USA)

	----------
	From:  Douglas Hurst Quebbeman [SMTP:dougq@iglou.com]
	Sent:  Tuesday, March 16, 1999 3:45 PM
	To:  quattro@coimbra.ans.net
	Subject:  Questions of an ur-Q Kind

	Well, Hello again... after an absence of a few months, I
	return to this indispensible wellspring of knowledge!

	Last year, I bought an 83 ur-Q, expecting it to be a
	project car, but hoping I could get some daily use out
	of it before proceeding. Couldn't get it to pass emission
	inspection, then one night, returning from a run to the
	store, it started backfiring badly, and could barely
	hold idle.

	I'd assumed it jumped a notch on the belt. It will still
	start, but idles rough. I took it to a local top-notch
	non-dealer repair place. He thinks it's likely the valves
	have kissed the pistons. He says he won't know till they
	get the head off, and we're many $$$ in by that point. He
	suggested he thought there might also be more problems, and
	quoted me about $2280 for a complete rebuild.

	Help!

	If the valves hit the pistons, won't the pistons show it?
	Shouldn't he be able to detect this by removing the spark
	plugs and using a borescope?

	I haven't asked him yet how much to just do an engine swap,
	because I recall WX engines are scarce as hen's teeth and
	twice as expensive. MC conversion seems the way to go but 
	I don't think I can afford his price to do it.

	Thoughts? Any of those $300 MC engines w/harness out there?

	As a final alternative, what I really need right now is a 
	backup for the daily driver (5ktq) since the Coupe tranny
	went all the way south. Anybody got a 4k in the 400-500
	range that won't break down for a year or so?

	As always, Thanks in Advance... -doug q
	--
	-Douglas Hurst Quebbeman (dougq@iglou.com)       [Call me "Doug"]
	    QuattroClub USA# 4536     Audi International # 100024
	       74 100LS Auto,   77 100LS Auto,   84 Coupe GT 
	           83 ur-Q,   86 5Kcstq QLCC 1.8bar  
	"The large print giveth, and the small print taketh away."  -Tom
Waits